Air Spring Bellows Cord Orientation for Torsion Durability
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Solution Overview
Problem
Conventional air springs face durability issues due to stress concentration and reduced torsion absorption ability, primarily caused by excessive torsion and rubber aging, leading to cord yarn damage and decreased ride comfort.
Innovation Solution
The air spring features a flexible bellows with internal and external cords aligned in parallel in non-motion portions and obliquely in the motion portion, combined with a jacket and a cold air supply system to prevent stress concentration and extend durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cross ply structure with internal and external cord layers is used to absorb torsion, then torsion absorption ability is improved, but cord yarns lose tensile force and become damaged due to excessive torsion
Solution Approach 1:
The bellows is divided into different sections with different cord layer configurations. The first section uses an axial ply structure with cord yarns parallel to the axial center line to maintain tensile force during torsion, while the second section uses a cross ply structure to prevent stress concentration. This local differentiation allows each section to perform its specific function optimally without compromising overall reliability.
2Reliability
If only an axial ply structure with cord yarns parallel to the axial center line is used, then cord yarn tensile force is maintained during steering, but stress concentration occurs in the rubber between cord yarns due to aging and heat
Solution Approach 1:
The bellows is segmented into a first section with axial ply structure and a second section with cross ply structure. The overlapping section connects these two sections. This segmentation allows the axial ply section to maintain cord yarn tensile force while the cross ply section prevents stress concentration in the rubber, thereby resolving the contradiction between cord yarn durability and rubber stress resistance.
3Strength
If the bellows length is increased to improve torsion absorption, then torsion absorption ability is improved, but the bellows becomes more susceptible to damage from frequent bending motions
Solution Approach 1:
Different sections of the bellows are assigned different cord layer structures based on their functional requirements. The first section with axial ply structure handles torsion absorption, while the second section with cross ply structure and the overlapping section are designed to withstand bending motions and prevent stress concentration, thereby improving overall durability without sacrificing torsion absorption capability.
Data Source
AI summary
An air spring may include a first end member and a second end member spaced from each other; a flexible bellows having a first end portion airtightly coupled to the first end member, a second end portion airtightly coupled to the second end member, and a jacket mounted on the circumference of the flexible bellows and configured to support the flexible bellows.